I recently upgraded to Stage 2 using the Cobb OTS 93 octane map. I'm running the COBB catted DP, and an STI catless uppipe. I don't have any exhaust leaks.

I specifically put a cat on so that I wouldn't get the smell I used to get in my catless Mustang.

I've datalogged and I'm running the correct AFR's according to Cobb and other research I've done.

My question is, is this normal? Is there a DP with a better cat that works better? I'm thinking the Invidia or Perrin might be better b/c the cat is closer to the turbo, so it should heat up quicker, get hotter, and therefore work better.

Now, to me, the exhaust smells like victory , but to my pregnant wife it smells gross and illegal. I'm also a little concerned I'm not being very environmentally friendly.

Also, will a custom tune help this smell? Would that be risky to run the car lean?

Did you put any exhaust wrap & spray on the DP? If so it could just be buring the spray off and it will eventually go away. Give it time and it should get better.

Oh and the Cobb DP is one of the best, I highly doubt that getting a perrin or invidia would change the smell (or a custom tune for that matter). However, a custom tune would give you more power and if done by an experienced/good tuner it would also be more reliable.

The smell is normal, and depending on how long or how hard you drive depends on how long the smell will take. Its just the oils and everything burning off the DP. I thought I had a problem with my Cobb TBE also, but you are fine. Sucks to hear about your wife though. Assure her that it will go away soon.

I've been at Stage 2 for about 3k miles. I bought the DP used with about 2k miles. Even though the DP was used I inspected it and the cat was not gutted or anything. He went to a rotated turbo kit so he couldn't use it anymore.

I think it's definitely from the exhaust and it smells just like my old catless Mustang and my friends catless Mustang that I was riding in today.

I guess I'm wondering my car smells like it's got no cat, but it does.

I don't think my Cobb dp smells either and I've put about 30,000 miles on it.

I suppose it's possible that the cat is going bad... they do have a life span and I'm sure a performance engine pushing extra waste gasses through it doesn't help lengthen that process, but I'd still give it a little more time and see what happens before you take any drastic measures.

Thanks for the responses. Maybe I'll have to go to a few meets and check out some other cars with Catted Cobb DP's. I only smell it at stop lights sometimes and when idling in the garage. It gets better after a few miles when the cat heats up, but I can still smell it.

I have a Cobb catted dp and a Borla Hush cat back. I'm running the OTS 93 octane stage 2 map. Mine smells but not the sulfur dioxide smell you'd get with no cat. I figured it was because the OTS map is so rich. I'll hopefully have my VF39 on next week and a custom map, we'll see if it changes any.